1. Field of the Invention
The present invention relates to a sheet feeding device which feeds sheets one by one from a storage storing a plurality of sheets, or an image forming device such as a printer and a copying machine, which are provided with the sheet feeding device.
2. Description of the Related Art
Conventionally, various types of sheet feeding devices have been proposed for use in an image forming device such as a printer and a copying machine, wherein the sheet feeding device separately feeds sheets one by one. Among the proposed feeding devices, there has been proposed a sheet feeding device using a so-called air separation method, according to which a plurality of sheets are floated for loosening by blowing air to the upper side end portion of a sheet stack, and a loosened sheet at the uppermost position is absorbed and conveyed on an absorption conveying belt. As various types of sheets may be surely and separately conveyed at high speed by the sheet feeding devices using the air separation method, higher demand for the sheet feeding devices has been caused in a print on demand (POD) field in which a large quantity of printing, simple bookbinding, and the like are performed, using an image forming device based on an electrophotographic method.
Among sheet feeding mechanisms using the air separation method, a technique has been disclosed in Japanese Patent Application Laid-Open No. 2005-96992, wherein, according to the technique, a type of a sheet is set, and air flow volume (air flow velocity) of a fan executing loosening operation is changed according to the type of the set sheet.
A sheet may be separately conveyed in a more sure manner by loosening a sheet at an optimum air flow volume (air flow velocity) according to the type of a set sheet as described above.
However, when copying, and printing is performed, using the image forming device, a user is required to set a sheet type. Thereby, when input miss, or input omission is caused at input of a sheet type by the user, there is a possibility that a sheet may not be separately conveyed in a secure manner.